Re: [PATCH] xen-block: fix segv on unrealize

[Stefan Hajnoczi]

Sorry!

Reviewed-by: Stefan Hajnoczi 

Re: [PATCH] xen-block: fix segv on unrealize

[Philippe Mathieu-Daudé]

On 6/6/23 15:16, Anthony PERARD via wrote:

From: Anthony PERARD 

Backtrace:
   qemu_lockcnt_lock (lockcnt=0xb4) at ../util/lockcnt.c:238
   aio_set_fd_handler (ctx=0x0, fd=51, is_external=true, io_read=0x0, 
io_write=0x0, io_poll=0x0, io_poll_ready=0x0, opaque=0x0) at 
../util/aio-posix.c:119
   xen_device_unbind_event_channel (xendev=0x55c6da5b5000, 
channel=0x55c6da6c4c80, errp=0x7fff641ac608) at ../hw/xen/xen-bus.c:926
   xen_block_dataplane_stop (dataplane=0x55c6da6ddbe0) at 
../hw/block/dataplane/xen-block.c:719
   xen_block_disconnect (xendev=0x55c6da5b5000, errp=0x0) at 
../hw/block/xen-block.c:48
   xen_block_unrealize (xendev=0x55c6da5b5000) at ../hw/block/xen-block.c:154
   xen_device_unrealize (dev=0x55c6da5b5000) at ../hw/xen/xen-bus.c:956
   xen_device_exit (n=0x55c6da5b50d0, data=0x0) at ../hw/xen/xen-bus.c:985
   notifier_list_notify (list=0x55c6d91f9820 , data=0x0) at 
../util/notify.c:39
   qemu_run_exit_notifiers () at ../softmmu/runstate.c:760

Fixes: f6eac904f682 ("xen-block: implement BlockDevOps->drained_begin()")
Signed-off-by: Anthony PERARD 
--
CC: Stefan Hajnoczi 
---
  hw/xen/xen-bus.c | 6 --
  1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index 1e08cf027a..ece8ec40cd 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -923,8 +923,10 @@ void xen_device_unbind_event_channel(XenDevice *xendev,
  
  QLIST_REMOVE(channel, list);
  
-aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh),

-   NULL, NULL, NULL, NULL, NULL);
+if (channel->ctx) {
+aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh),
+   NULL, NULL, NULL, NULL, NULL);
+}
  
  if (qemu_xen_evtchn_unbind(channel->xeh, channel->local_port) < 0) {

  error_setg_errno(errp, errno, "xenevtchn_unbind failed");


Reviewed-by: Philippe Mathieu-Daudé 

[PATCH] xen-block: fix segv on unrealize

[Anthony PERARD via]

From: Anthony PERARD 

Backtrace:
  qemu_lockcnt_lock (lockcnt=0xb4) at ../util/lockcnt.c:238
  aio_set_fd_handler (ctx=0x0, fd=51, is_external=true, io_read=0x0, 
io_write=0x0, io_poll=0x0, io_poll_ready=0x0, opaque=0x0) at 
../util/aio-posix.c:119
  xen_device_unbind_event_channel (xendev=0x55c6da5b5000, 
channel=0x55c6da6c4c80, errp=0x7fff641ac608) at ../hw/xen/xen-bus.c:926
  xen_block_dataplane_stop (dataplane=0x55c6da6ddbe0) at 
../hw/block/dataplane/xen-block.c:719
  xen_block_disconnect (xendev=0x55c6da5b5000, errp=0x0) at 
../hw/block/xen-block.c:48
  xen_block_unrealize (xendev=0x55c6da5b5000) at ../hw/block/xen-block.c:154
  xen_device_unrealize (dev=0x55c6da5b5000) at ../hw/xen/xen-bus.c:956
  xen_device_exit (n=0x55c6da5b50d0, data=0x0) at ../hw/xen/xen-bus.c:985
  notifier_list_notify (list=0x55c6d91f9820 , data=0x0) at 
../util/notify.c:39
  qemu_run_exit_notifiers () at ../softmmu/runstate.c:760

Fixes: f6eac904f682 ("xen-block: implement BlockDevOps->drained_begin()")
Signed-off-by: Anthony PERARD 
--
CC: Stefan Hajnoczi 
---
 hw/xen/xen-bus.c | 6 --
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index 1e08cf027a..ece8ec40cd 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -923,8 +923,10 @@ void xen_device_unbind_event_channel(XenDevice *xendev,
 
 QLIST_REMOVE(channel, list);
 
-aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh),
-   NULL, NULL, NULL, NULL, NULL);
+if (channel->ctx) {
+aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh),
+   NULL, NULL, NULL, NULL, NULL);
+}
 
 if (qemu_xen_evtchn_unbind(channel->xeh, channel->local_port) < 0) {
 error_setg_errno(errp, errno, "xenevtchn_unbind failed");
-- 
Anthony PERARD